The present invention is directed generally to a recording/reproducing device for use with, e.g., a computer and a word processor, and more particularly, to a recording/reproducing device for recording or reproducing pieces of desired information on or from a recording medium such as a floppy disk.
A typical arrangement of this type of recording/reproducing device is that a frame of an apparatus body accommodates a disk driving motor, a carriage having upper and lower heads, a carriage driving motor for moving the carriage and a circuit board incorporating a circuit for controlling operations of the motor and a lead light  read/write head; and the recording medium is loaded into the device to effect recording or reproducing. In recent years, it is desired that the recording/reproducing device be small both in configuration and in thickness with an increasing demand for miniaturizing the computers.
A prior art recording/reproducing device disclosed in Japanese Utility Model Laid-Open Publication No. 62-147197 is illustrated in FIGS. 38 and 39. FIG. 38 is a vertical sectional side view of the prior art recording/reproducing device. FIG. 39 is an enlarged view depicting the principal portion thereof.
As illustrated in the Figures, a spindle motor 502 serving as a motor for driving the carriage is mounted from underside of a frame 501 in the Figures. Disposed on an upper surface of the spindle motor 502 is a lower carriage 503 fitted with a lower head, on which an upper carriage 504 having an upper head 508  506 is mounted about a rotary fulcrum. A jacket is held between the lower and upper carriages 503 and 504. Provided on the recording/reproducing device is a holder 505 which moves between a position in which to insert a jacket J and a recording/reproducing position. The upper carriage 504 mounted with the upper head includes a lift member 504a to separate the upper carriage 504 from the jacket J in linkage with a motion of the holder 505 moving between the inserting position of the jacket J and the recording/reproducing position.
For this purpose, in the recording/reproducing device catered for, e.g., a recently developed lap-top computer, as the above-mentioned demand for decreasing a thickness of the device grows, it is required to reduce both a clearance cl between the upper carriage 504 depicted in FIG. 39 and an outer circumference of the recording/reproducing device and a clearance c2 between the upper head 506 and the jacket J. Based on the prior arts, however, an amount of movement of the upper carriage 504 is determined by a lifting/lowering quantity of the holder 505. The upper carriage 504 is constructed to rotate about a fitting part to the lower carriage 503, and hence a scatter with respect to the lifting member 504a of the upper carriage 504 is expanded several times in a position of the upper head 506 at the top of the upper carriage 504. When making an attempt to enlarge the clearance c2 between the jacket J and the upper head 508  506, the upper carriage 504 grows in configuration in excess of predetermined dimensions of the recording/reproducing device; or reversely, when the priority is given to the dimensions of the recording/reproducing device, it is impossible to obtain a sufficient clearance c2 between the jacket J and the upper head 508  506. This situation leads to a problem in which the jacket J acts to damage the upper head 506.
A rotary driving mechanism for a disk in the above-mentioned recording/reproducing device is disclosed in, for instance, Japanese Utility Model Laid-Open Publication No. 61-52351. The construction thereof is depicted in FIGS. 40 through 43. Turning to FIG. 40, there is illustrated a plan view of a conventional disk rotary driving unit. FIG. 41 is a bottom view thereof. FIG. 42 is a vertical sectional view thereof. FIG. 43 is a sectional view schematically illustrating a driving pin part thereof.
In these Figures, the symbol D denotes a disk, and H represents a hub thereof. These components are drawn with dotted lines in FIGS. 40 and 41  FIG. 42. The reference numeral 510 designates a rotary driving shaft of the disk D. A chucking lever 512 is pivotally supported about a fulcrum 513 on a rotary plate 511 rotating together with the driving shaft 510. A spring 515 imparts an axial bias to a driving pin 514 fitted to the chucking lever 512, while rotational bias is given by a spring 516. The chucking lever 512, when the hub H is set to be chucked, as illustrated in FIG. 43, escapes in an arrowed direction r in the Figure while being pushed by the hub H, so far  long as a rotary driving hole h2 located eccentrically from the center of the hub H does not align in position with the driving pin 514. Next, as depicted in FIG. 42, the driving pin 514 rotates together with the rotary central shaft 510 by initiating rotations of a rotor 518 of a disk driving motor 517 mounted on an end of the rotary driving shaft 510. Just when the rotary driving hole h2 aligns with the driving pin 514, this pin 514 is protruded into the rotary driving hole h2 by dint of the spring 515. On the basis of a positional relationship of the driving pin 514 with respect to the fulcrum 513, as illustrated in FIG. 40, the driving pin 514, when rotating the hub H, generates a force acting in an arrowed direction s of the Figure and a force for rotating the hub H. The force in the arrowed direction s of the Figure acts to thrust two inner points of a central hole h1 of the hub H against the rotary driving shaft 510, thereby effecting a rotary drive while seeking the center of the hub H. The lower head 519 for recording and reproducing signals on and from the disk D is disposed between a frame 520 of the motor 517 and the disk D.
Based on this construction, according to the prior art discussed above, when trying to reduce the thickness of the recording/reproducing device, thicknesswise dimensions are conditional to a space for accommodating the rotor 518 of the motor 517, the lower carriage 521, the lower head 519 and the chucking mechanism. This is an obstacle against the reduction in thickness of the device.
In particular, as depicted in FIG. 43, the driving pin 514 is pushed by the hub H when chucking the hub H and is moved in the arrowed direction r in the Figure, resulting in provision of a futile space.
An additional example is a recording/reproducing device reported on Nikkei Electronics Journal, NO.394 issued in 1986 5xe2x80x945. This recording/reproducing device is, as illustrated in FIG. 44, constructed such that a disk driving motor 525 is provided coaxially with the disk D defined as a recording medium, a bearing 525a of the motor 525 is fitted in a positioning hole 526a bored in a frame 526, and a motor base 527 is fixed to the frame 526 with Screws  screws.
Upper and lower carriages 530 and 531 mounted with upper and lower heads 528 and 529 are guided by a guide shaft 532. Movement positioning in an arrowed direction j  t of the Figure is effected by use of an unillustrated stepping motor conceived as a carriage driving motor. Attached to a lower surface of the guide shaft 582  532 in the Figure is a circuit board for controlling the disc driving unit and converting signals transmitted from the heads.
Besides, the lower carriage 581  531 is arranged to move up to an upper surface of the rotor 525b of the disk driving motor 525 in the Figure.
For this reason, in the case of decreasing the device thickness, it is necessary to make thin both the motor and the frame, because the disk driving motor is disposed downwardly of the frame. It is therefore difficult to reduce the device thickness. A further obstacle against the decrease in the device thickness is the arrangement that a control board is attached to a lower surface of the carriage. It is because the carriage is overlapped thicknesswise with the control board. The carriage is intruded up to an upper surface of the rotor of the disk driving motor, resulting in the difficulty of reducing the device thickness because of superposing the carriage thicknesswise on the rotor.
A loading/ejecting mechanism of the disk in the prior art recording/reproducing device is constructed in the following manner. FIG. 45 is a plan view schematically illustrating one example of the conventional recording/reproducing device. FIGS. 48  46 and 47 are vertical sectional side views schematically depicting a standby state of loading a jacket accommodating the disk and a state of mounting the jacket.
Referring to these Figures, a shutter releasing lever 535 is provided at its one end with an operating pin 586  536 for releasing a shutter (not shown) of the jacket by engaging with the shutter. The other end of the lever 535 is so fitted to a holder 537 for holding the jacket as to be ratable  rotatable about a fulcrum pin 538. The lever 535 is constantly so biased as to be rotatable clockwise in FIG. 45. On a side surface of the holder 537, a plurality of rolling roller pins 537a serving as interlocking means are fixed to rolling rollers 537b to permit rotations of the rolling rollers 537b, the pins 537a being biased in an arrowed direction X1 by a holder spring 541 while engaging with holder guide grooves 540a of a frame 540. The roller pins 537a are positioned to permit impingement upon lifting/lowering cam portions 542a of a cam member 542 depicted in FIGS. 46 and 47. The cam member 542 is supported on a jacket guide receiving portion 543 conceived as a jacket supporting means embedded into the frame 540 and on a part of a jacket receiving pin 544 serving as a position regulating means. The cam member 542 is so disposed as to be slidable in arrowed directions x1 and x2 and is also biased in the arrowed direction x1 by a cam member spring 545. An eject member 546 depicted in FIG. 45 is axially supported on a shaft 547 embedded into the frame 540 and rotationally biased anticlockwise in FIG. 45 by means of an eject member spring 548. The eject member 548  546 includes an impingement portion 546a which impinges upon a part of the jacket J. The jacket K  J, when being inserted or pulled out, collides with the impingement portion 548a  546a, whereby the eject member 548  546 rotates about the shaft 547.
Fixed to a part of the cam member 542 is an eject button 549 illustrated in FIGS. 48  46 and 47 in close proximity to a dressing plate 550 attached to the frame 540.
Based on such a construction, as illustrated in FIG. 46, the jacket J is inserted from an insertion port 550a in the direction x2, in which state the operating pin 536 fixed to the shutter releasing lever 535 shown in FIG. 45 engages with the shutter of the jacket J. The shutter releasing lever 535 is thereby rotated about the fulcrum pin 538 in the anticlockwise direction of FIG. 45 while opening the shutter. Upon a further insertion of the jacket J in the arrowed direction x2 of FIG. 46, the jacket J impinges on the impingement portion 546a of the eject member 546, with the result that the eject member 546 starts rotating clockwise about the shaft 547 in FIG. 45 while resisting the biasing force of the eject member spring 548. When being further intruded, the jacket J abuts against an impingement portion 537d of the holder 537, thereby moving the holder 537 in the arrowed direction x2, resisting the biasing force of the holder spring 541. As shown in FIG. 46, the plurality of rolling rollers 537b provided on the side surface of the holder 537 are moved down along the guide groove 540 chased in the frame 540 in an arrowed direction z2 by means of the holder spring 541.
On the other hand, the jacket J inserted into the holder 537 is supportingly received by the jacket receiving pin 544 embedded into the frame 540 and by the jacket receiving portion 843  543, thus effecting a predetermined positioning process. Subsequently the jacket is seated as illustrated in FIG. 47, in which position recording and reproducing are to be performed.
Next, in the case of ejecting the jacket J, the eject button 549 is depressed in the direction x2 from a state of FIG. 47. Then, a lifting cam portion 542a of the cam member 542 impinges upon the rolling roller 537b of the holder 537, whereby the holder 537 holding the jacket J slides upwards along a holder guide groove 540c formed in the frame 540. Immediately, the eject member 546 is rotated anticlockwise in FIG. 45 by the biasing force of the eject member spring 548, and the jacket J is thereby ejected in the arrowed direction x1. At this time, the shutter releasing lever 535 is made to revert to a position indicated by a solid line of FIG. 45 by dint of a tensile coil spring 539, thus finishing an ejecting operation.
In the above-mentioned prior art jacket loading/ejecting mechanism, however, the cam member 542 guided by the guide pin embedded into the frame 540 slides in the jacket inserting/removing directions to thereby move the holder 537 horizontally to the jacket inserting/removing position and further to the recording/reproducing position. As a result, a load associated with rectilinear sliding of the cam member 542 becomes large, and the cam member 542 increases in configuration because of requiring guide pins 543 and 544 for guiding the holder 537 and also a support member for moving the holder while holding it horizontally. Besides, the cam member has to be disposed between the holder and the frame, resulting in a problem in terms of space.
If the jacket is mistakenly inserted, the jacket is intruded from the insertion port 550a of the dressing plate 550 of FIG. 46 in the arrowed direction X2 in such a state, for example, the surfaces or the front and the rear of the jacket are reversed. At this time, the operating pin 536 provided on the shutter releasing lever 535 impinges on the top end surface of the jacket J, thereby rotating the lever 535 anticlockwise in FIG. 45. When the insertion continues, the shutter releasing lever 535 is further rotated in the same direction and behaves to thrust forward the holder 537 while abutting against an impingement portion 537e of the holder 537. For this reason, the result is that the same fitting operations are carried out following a trajectory identical with that in the inserting process in the above-described normal state. Consequently, the components incorporated in the device are to be damaged. The cam member 542 is, as discussed above, supported on the jacket receiving portion 543 conceived as a jacket supporting means embedded into the frame 540 as well on a part of the jacket receiving pin 544 defined  defining a position regulating means. The cam member 542 is so located as to be slidable in the arrowed directions X1 and x2 and includes the cam portion 542a on which the plurality of rolling rollers 537b provided, as depicted in FIG. 48,  46 on the side surface of the holder 537 impinge. With this arrangement, when sliding the cam member 542, the sliding portion increases in area, and there are needed parts for guiding and holding the cam member 542. Provision of the cam member 542 entails formation of a gap between the frame 540 and the holder 537, and an additional problem is that the configuration becomes large because of the parallel movement of the holder 587.
As stated earlier, the conventional reproducing device presents a variety of obstacles against miniaturization of the device (reduction in the device thickness).
In a recording/reproducing device developed in recent years as an external storage unit of a variety of electronic appliances associated with computers, there are widely spread a floppy disk drive (hereinafter abbreviated to FDD). A  , a hard disk drive (abbreviated to HDD), an optical disk drive (abbreviated to ODD) and a tape streamer. Sizes of outer shapes and fitting dimensions thereof are substantially standardized depending on a size of the recording medium. Take the FDD for instance, typically three types of FDDs are available, i.e., a 3.5-inch type, d  a 5.25-inch type (generally known as a 5-inch type and the representation is the same with this description) and a  an 8-inch type. The recording medium used for a single unit of electronic appliance typically comes under one size, which causes inconvenience in terms of general purposes.
To cope with this, there was proposed a recording/reproducing device capable of recording and reproducing by employing both an initially used disk and another disk having a different size, the device being disclosed in, Japanese Utility Model Laid-Open Publication No.63-11792. The construction thereof is shown in FIGS. 48 and 49.
Turning first to FIG. 48, there is illustrated a perspective view of an outline of the conventional recording/reproducing device in an electronic appliance such as a computer. FIG. 49. is a front elevation thereof.
An arrangement of the recording/reproducing device, depicted in FIGS. 48 and 49, for use with the electronic appliance is given as follows. For example, a 3.5-inch standardized recording/reproducing device 603 in accordance with a recent tendency of miniaturization incorporated in a chassis 602 of an electronic appliance body 601, the chassis 602 having the same size and the same mounting structure as those of the chassis of the FDD (hereinafter referred to as a 5-inch standardized FDD) which is standardized corresponding to, e.g., an initially used 5-inch disk. Attached to a front surface of the chassis 602 is a front bezel 604 having much the same size as that of, e.g., a 5-inch FDD. The front bezel 604 is formed with an insertion port 604a for loading the inch disk. Provided in rear of the recording/reproducing device 603 is a relay board 605 exhibiting the same interface function as that of, e.g., the 5-inch FDD. In a variety of electronic appliances each mounted with, e.g., the 5-inch FDD and composed of a body 601 formed with an opening for admitting the front bezel, the recording/reproducing device is completely replaceable with the 5-inch FDD.
The above-mentioned type is, however, classified as, e.g., a 3.5-inch recording/reproducing device miniaturized smaller than the 5-inch FDD and having an interface function identical with that of the 5-inch FDD. For instance, in many kinds of electronic appliances each mounted with, e.g., 5-inch FDD, the recording/reproducing device is completely replaceable with the 5-inch FDD. Hence, when replacing the recording/reproducing device even in a system which has hitherto been utilized, software recorded on a 3.5-inch recording medium can be used instead of the software which has already been recorded on a 5-inch recording medium in the conventional system as it is. The initial purpose can thus be accomplished. There arise, however, the following defects in association with a technical tendency of nowadays.
There can be seen a remarkable advancement in technologies pertaining to a variety of electronic appliances related to up-to-date computers. In particular, a technical enhancement combined with the software is most sophisticated, and therefore the softhouse-based  software-based business is aggressively expanded.
The softhouse-based  software-based business is developed with brains, and its technical growth is increasingly accelerated. On the other hand, it is required that a good deal of assets be invested in the development of technologies of hardware, i.e., multiple computer-based electronic appliances. Life cycles of the hardware are relatively long as compared with the software, and it is not easy to improve the hardware because of requiring highly sophisticated techniques of specialty. In the actual systems, there still exist hardware here and there which can not come up with the technical advancement on the part of software. This is the real situation. This imbalance may be a big obstacle against the development of the general system. What is needed especially in the sector of software technologies is to facilitate an expansion of the general system by freely systematizing the FDDs, HDDs, ODDs and tape streamers which have been standardized and spread over as external storage devices of many kinds of electronic appliances.
Accordingly, it is the first object of the present invention, which has been devised under such circumstances, to miniaturize the recording/reproducing device to the greatest possible degree, and particularly, to reduce a thickness thereof.
Another object of the invention is to shrink a space for accommodating a variety of electronic appliances such as computers by virtue of the reductions both in configuration and in thickness of the recording/reproducing device and also to facilitate both functional improvements thereof and an expansion of the system.
According to the present invention, there is provided a recording/reproducing device comprising: at least a disk driving motor described above; a carriage including upper and lower heads; a carriage driving motor; a circuit board having a circuit for controlling operations of a read/write and of the motors; and a device body frame. The recording/reproducing device is made as small, i.e., thin as possible. To be more specific, a thickness of the device as a whole is set smaller than 20.5 mm.
A means for making the device thin is attained by taking the following components and arrangement.
For example, a rotor magnet of the disk driving motor involves the use of a rare earth group magnet. Where the rare earth magnet is employed, the same or higher performance than in the prior art can be secured even if the magnet is smaller than the conventional one. Hence, an outside diameter or an axis-directional length of the disk driving motor can be reduced. The rare earth group magnet is effective especially in reducing the thickness of the whole device when employing a spindle motor coaxial with the disk as a disk driving motor.
If the placement is made without causing planar overlapping of the carriage having the upper and lower heads with the disk driving motor, the device can be decreased in thickness on the whole. In the case of disposing a circuit board and a guide shaft with a deviation on the plane, the device thickness can likewise be reduced. Where neodymium ferrous boron is used as a rotor magnet for the carriage driving motor, sufficient torque can be obtained even in the case of miniaturization, and the whole device can be decreased in thickness.
Besides, it is possible to make the device still thinner by adequate and selective combinations of the above-described arrangements. The reduction in the device thickness contributes to a shrinkage of the space for incorporating the recording/reproducing device of the invention into an electronic appliance like, e.g., a computer. Especially when setting the device thickness to 20.5 mm or under, it is practical to mount two or more devices in a disposing space for a single unit of prior art device on the occasion of installing the recording/reproducing device of the invention instead of the existing recording/reproducing device the thickness of which is typically set to 41 mm as in a conventional 5-inch floppy disk drive.